Posts tagged with Stephen Vantassel

Late Tuesday I received word that Indian Harbour Beach, Florida, went through with its proposed ordinance, thereby making it illegal: “for any person to possess, harbor, feed, breed, maintain or keep any feral animals on any public or private property located within the corporate boundaries of the City of Indian Harbour Beach.”

“Cat Fight,” which appears in the latest issue of Conservation magazine, does little to cut through the rhetoric or clear up the numerous misrepresentations that plague the debate over free-roaming cats.

There is, it’s often said, no such thing as bad PR. Even so, I’m not thrilled with the way I’m portrayed in an article appearing in the current issue of Conservation.It’s only a couple of quotes, but still, I worry that I come off as more of a bomb-thrower than anything else.

“Wolf writes a blog, Vox Felina,” explains writer John Carey, in “Cat Fight,” “which regularly excoriates wildlife biologists for what Wolf calls their ‘sloppy pseudo-science.’ He charges that ‘the science in Dauphine’s paper about cats was so horrific that she should have never made it out of graduate school’ and that ‘Peter Marra is taking six bird deaths and predicting the Apocalypse.’”

As I told Carey via e-mail, just after the piece was published online, I don’t believe the quotes are accurate. Carey, on the other hand, assures me (in a cordial, professional manner typical of our exchanges) that “the quotes are exactly what [I] said.” (Neither of us recorded our conversation.)

“I know I realized immediately when you said those things that they were precisely the type of colorful statements that illustrate the nature of the debate, so I did appreciate you using such colorful language.”

Fair enough. Perhaps it’s not all the important if the content isn’t precisely correct—the tone is certainly accurate.

If I am a bomb-thrower, though, I am at least a well-informed bomb-thrower. And the “targets”—to extend the metaphor—have, simply put, got it coming to them. Carey acknowledges that I “do an excellent job scrutinizing the scientific evidence, and have clearly thought deeply about both sides of the issue.” Unfortunately, that doesn’t come across to Conservation readers.

That said, I want to make it clear: I’m grateful to have been included in the piece, and grateful, too, for my conversations with Carey. And whatever quibbles I have about my portrayal pale in comparison to various other aspects of “Cat Fight.”

Certainly, this was the message Marra emphasized to the press—but I thought I’d straightened this out with Carey on the phone, and with a follow-up e-mail.

Here’s what Marra and his colleagues report in their paper:

A total of 69 fledglings were monitored, of which 42 (61 percent) died over the course of the study. Of those mortalities, 33 (79 percent) were due to predation of some kind. Eight of the 33 predatory events were observed directly: six involved domestic cats, one a black rat snake, and one a red-shouldered hawk.

That leaves 25 predation events (76 percent) for which direct attributions could not be made—which, in and of itself, raises serious questions about Carey’s “number one predator” claim.

About those other 25: Marra and his co-authors concede that “not all mortalities could be clearly assigned.” Seven were attributed to rats or chipmunks because they were “found cached underground,” while another one was attributed to birds because the remains were found in a tree.

In addition, 14 mortalities “could not be assigned to a specific predator.” Which leaves three: “fledglings found with body damage or missing heads were considered symptomatic of cat kills.” [2]

In fact, it’s rather well known that such predatory behavior is symptomatic not of cats, but of owls, grackles, jays, magpies, and even raccoons [3–5]—something I addressed in an October 2010 post (and discussed with Carey).

All of which is difficult to reconcile with Marra’s claim, in “Cat Fight,” that he and his colleagues “were very conservative assigning mortality to cats,” [1] and with his apparent confidence (shared by Carey) in putting cats at the top of the list.

Curious, too, that, although Carey opens his article with Nico Dauphine’s December 2011 sentencing hearing, he never mentions the fact that Marra was Dauphine’s advisor at the Smithsonian Migratory Bird Center. (I suppose the connection isn’t something Marra brags about these days.)

The Cats Came Back
Carey argues that “moving cat colonies away from areas that harbor threatened species is a no-brainer” but points out that “it doesn’t always work.”

“In Fortescue, New Jersey, a colony of feral cats was moved away from the shore of Delaware Bay in 2011 to help protect red knots, which stop there in huge numbers to gorge on horseshoe-crab eggs to fuel their long migration from the tip of South America to the Arctic. But after only a few months, cats were back.” [1]

“The details about the Fortescue cats, with which I was involved, are incorrect. The colony was not ‘moved,’ it was removed completely. 40 cats were moved to a fence enclosure on a farm several counties away, 7 went to a sanctuary in another state, others went to barns or were friendly enough to be adopted. Removal was used, which is what the anti-TNR people always want. The only difference is the cats were not killed—something that was possible because of limited numbers. It is true that, due to the vacuum effect, different cats then showed up. The nonprofit doing the removal keeps trapping there in coordination with animal control to try to get them all. A few per month show up. But this is why TNR advocates warn removal never really works without intensive management and repeat trapping, and why statistical studies have shown it takes 10 times the effort to control a colony through removal as through TNR. Because there is a reason the cats were there in the first place and more will just move in—more who are unneutered—if the cats are removed.”

It’s worth pointing out, too, that, unlike the current relocation effort, taxpayers would be footing the bill for an ongoing lethal roundup.

And I wish Carey had included a bit of additional context here. The greatest threat to those red knots, from what I can tell (admittedly, doing nothing more than a quick Google search), has little to do with cats being fed nearby. According to The Wetlands Institute:

“…overharvesting of female horseshoe crabs by commercial fishermen, coupled with loss of spawning habitat resulting from beach erosion associated with sea level rise, has resulted in a precipitous decline in the Delaware Bay horseshoe crab population, and therefore the number of eggs available to feed migratory birds. This, in turn, has led to a dramatic decrease in the size of annual red knot migrating populations, to the point that red knots have been proposed for federally endangered status.”

The Scientific Community v. The People of the District of Columbia
If Marra hasn’t come to Dauphine’s defense, Chris Lepczyk has—with the kind of confidence he (and Marra) usually reserve for vilifying free-roaming cats.

“‘I am 100 percent confident she was not poisoning cats,’ says University of Hawaii wildlife ecologist Christopher Lepczyk, who fears that she was convicted in part because of her articles about the cat-predation problem. ‘I don’t think anyone in the scientific community agrees that she is guilty.’” [1]

That’s quite an endorsement—especially in light of… you know, the facts.

On December 14th, the day Dauphine was sentenced, CNN reported that Superior Court Judge A. Truman Morrison III “said he had received a number of letters from people who know Dauphine.”

“He said such letters usually try to make a case that the verdict was in error, but in this case, the judge said, no one quarreled with the guilty verdict… Morrison said it was clear from letters written by Dauphine’s colleagues that ‘her career, if not over, it’s in grave jeopardy.’ The judge said that was already partial punishment for her actions.”

But Lepczyk’s right when he says the verdict was, in part, the result of Dauphine’s writings—just not in the way he suggests. Indeed, the day Dauphine was found guilty, The Washington Post reported: “Senior Judge Truman A. Morrison III said it was the video, along with Dauphine’s testimony, that led him to believe she had ‘motive and opportunity.’”

“He specifically pointed to her repeated denials of her writings. ‘Her inability and unwillingness to own up to her own professional writings as her own undermined her credibility,’ Morrison said.”

All of which—not to put too fine a point on it—was included in my numerous posts following the case. Perhaps Lepczyk ought to subscribe to Vox Felina.

I’ve been saying for nearly two years now that Dauphine’s professional work on the subject of free-roaming cats—cited and promoted with great enthusiasm before all this nasty press attention—is as indefensible as the actions that landed her in DC Superior Court. It’s a shame Carey didn’t pin down Lepczyk (and others) on that point.

Referring to the toll cats take on wildlife, Vantassel told Carey, “The numbers are mind-numbing.” [1]

Actually, “mind-numbing” is a fitting description for the content of, and motivation behind, Feral Cats and Their Management, the well-publicized paper Vantassel co-authored in late 2010. Not only do the authors fail to get a handle on the predation numbers, they reveal a significant lack of understanding of the key issues surrounding cats and predation in general. Indeed, they misread, misinterpret, and/or misrepresent nearly every bit of research they reference. And, some of what the authors include isn’t valid research to begin with.

Two years later, it seems he’s still got nothing to contribute to the discussion.

OK, maybe that’s being too harsh. Consider what Vantassel has to say, in the sidebar that accompanies “Cat Fight,” about the uncertainty surrounding the legal status of free-roaming cats: it “has essentially turned outdoor cats into protected predators.” [6]

Protected predators?

Now, here’s a subject Vantassel knows well. After all, his PhD (theology) dissertation was dedicated to: “…fur trappers who, every winter, brave the harsh weather in continuance of America’s oldest industry. Regrettably, they must also endure the ravages of urban sprawl and the derision of an ungrateful and ignorant public.” [7]

“In a landmark study in Wisconsin, Stanley Temple, now professor emeritus of forest and wildlife ecology at the University of Wisconsin, and his colleagues radio-collared free-ranging rural cats, watched the animals’ hunting behavior, and examined their stomach contents. (An inflammatory and inaccurate press report that implied that the researchers had killed the cats for the stomach contents—in fact, they used an emetic—led to death threats against Temple.) The study showed that each cat killed an average of 5.6 birds a year. With an estimated 1.4 million free-ranging rural cats just in Wisconsin, that’s nearly 8 million birds.” [1]

When I spoke with Carey, he’d already talked to Temple. And when he referred to a predation study Temple had done, I stopped him in his tracks: If Temple conducted any such work, it was never published.

What has been published involved combining cat density numbers Temple and graduate student John Coleman had gathered by surveying “farmers and other rural residents in Wisconsin for information about their free-ranging (not house-bound) cats” [8] with predation numbers from studies conducted in the 1930s and 1950s. All of which is explained in a 1992 article the two wrote for Wildlife Control Technology:

“…our four year study of cat predation in Wisconsin, completed in1992, coupled with data from other studies, allows us to make a reasonable estimate of birds killed annually in this state… At the high end, are estimates from diet studies of rural cats that indicate at least one kill per cat per day, resulting in over 365 kills per cat per year [9–11]. Other studies report 28 kills per cat per year for urban cats, and 91 kills per cat per year for rural cats [12].” [13]

“Using low values,” then, Temple and Coleman multiplied their estimated 1.4 million rural free-roaming cats in the state by 28 (“twice urban kill rate”), and then multiply that by 20 percent (the “low dietary percent,” as they call it, though it’s actually a gross misinterpretation of Mike Fitzgerald’s work, as Ellen Perry Berkeley points out in her 2004 book TNR Past Present and Future: A history of the trap-neuter-return movement [14]). The resulting “estimate” is “7.8 million birds killed annually.”

Twenty years later, though, the story seems to have changed dramatically.

Now, we’re to believe that Temple and Coleman’s study (funded, by the way, with “about $100,000 … from the [University of Wisconsin], U.S. Agriculture Department and the state Department of Natural Resources” [15]) revealed an average predation rate of 5.6 birds/year/cat. And that the 7.8 million figure comes not from “coupling” Temple and Coleman’s density work with others’ predation studies, but from their work alone.

Or perhaps the two methods resulted in exactly the same estimate.

Which, as I told Carey after reading the article, would beone hell of a coincidence. In fact, the very sources he cites call into question—if not discredit entirely—Temple’s claim.

Simply put: Carey failed to dig into this deeply enough. Instead of further perpetuating the myth of the Wisconsin Study, he might have exposed it for what it is: little more than a few misguided (and overpriced) back-of-the-envelope calculations—which Temple himself backed away from during a 1994 interview with The Sonoma County Independent: “They aren’t actual data; that was just our projection to show how bad it might be.” [16]

Or, failing that, then at least ignore the thing entirely.

Landmark study? Only insofar as it was instrumental in launching what’s become a witch-hunt against free-roaming cats in this country.

• • •

According to the magazine’s website, “Conservation stories capture the imagination and jump-start discussion.” Unfortunately, I don’t see “Cat Fight” adding much to the discussion—a missed opportunity in a debate where such opportunities are few and far between.

I agree with Carey that, as he notes in the article’s closing paragraph, “these great societal debates … are contested on a battleground of conflicting emotions, moral values, and ideologies. Facts alone rarely break up the fight.”

On the other hand, I don’t see how we’re going to break it up if we don’t first get the facts straight.

“The cat, of all animals, is in some respects the most intimate companion of man… Nevertheless, it leads a dual existence. ‘The fireside sphinx,’ the pet of the children, the admired habitué of the drawing-room or the salon by day, may become at night a wild animal, pursuing, striking down and torturing its prey, frequently making night hideous with its cries, sneaking into dark, filthy, noisome retreats, or taking to the woods and fields, where it perpetrates untold mischief. Now it ravages the dovecote; now it steals on the mother bird asleep on her nest, striking bird, nest and young to the ground. In the darkness of night it turns poacher. No animal that it can reach and master is safe from its ravenous clutches.” —Edward Howe Forbush, The Domestic Cat: Bird Killer, Mouser and Destroyer of Wild Life; Means of Utilizing and Controlling It (1916)

In the January/February issue of Animal People, editor Merritt Clifton confirms his “hunch that ‘Feral Cats and Their Management’ is little more than a paraphrased and condensed update of the 1916 tract The Domestic Cat: Bird Killer, Mouser and Destroyer of Wild Life; Means of Utilizing andControlling It, authored by then-Massachusetts state ornithologist Edward Howe Forbush.”

“…the University of Nebraska paper and the Forbush work follow almost identical outlines from beginning to end, making similar allegations, arriving at the same recommendations in closely parallel language.” [1]

“The major structural difference,” writes Clifton, has to do with the sources involved. Whereas Forbush relied largely on “anecdotal testimony from more than 200 individual correspondents” (much of it from hunters who were after the same birds the cats were pursuing), Hildreth, Vantassel, and Hygnstrom provide “no firsthand testimony.” [1]

Instead, notes Clifton, they “plugged in references to more recent studies… in support of essentially the same claims, including that cats devastate populations of birds who would otherwise be hunted.” [1]

Among the similarities described in Clifton’s article:

Fecundity
Like Forbush, the authors of “Feral Cats and Their Management” use “outlandishly high claims about feline fecundity” [1] to drum up support for their eradication (“Hence the necessity for checking such increase promptly by killing all superfluous kittens soon after birth,” [2, p. 19] as Forbush put it).

For their reprise of Bird Killer, Mouser and Destroyer of Wild Life, Hildreth, Vantassel, and Hygnstrom turn to a frequently cited—but bogus—figure:

“The Humane Society of the United States estimates that a pair of breeding cats and their offspring can produce over 400,000 cats in seven years under ideal conditions, assuming none die.” [3]

But of course, feral cats—like all animals, and especially those living outdoors—don’t live “under ideal conditions.” And kittens do die. (The fact that Hildreth, Vantassel, and Hygnstrom leave it that is telling: their intent has nothing whatsoever to do with science, or research of any kind.)

Predation and Impact
Clifton points out that Forbush ignored reliable information indicating that free-roaming cats kill, on average 10 or 11 birds annually, and instead “dwelt on the claims of 15 people that their cats killed 20.4 birds per month, and the claims of six people that their cats killed about 50 birds per year.”

It’s not clear what information Hildreth, Vantassel, and Hygnstrom relied on, as they didn’t bother with in-text citations. Whatever the source, the authors settled on a surprisingly conservative annual predation rate of eight birds per year, and used 60 million as the estimated number of feral cats in the U.S. This, too, might be considered conservative in light of other “estimates,” (the American Bird Conservancy, for example, claims—without citing any source—that the population is 120 million) though Clifton himself estimated, in 2003, that “the winter feral cat population may now be as low as 13 million and the summer peak is probably no more than 24 million.” [4]

“Although cats can carry diseases and pass them to people, you are not likely to get sick from touching or owning a cat… People are probably more likely to get toxoplasmosis from gardening or eating raw meat than from having a pet cat.”

• • •

“Much of Forbush’s antipathy toward cats,” suggests Clifton, “might be ascribed to the context of the times.”

“His life coincided with the era in which New England wildlife was more depleted than at any time since. Logging, ploughing, damming, and unrestrained development depleted the forest cover, the grasslands, and the rivers. Precocious as Forbush was in his birding, which then was done chiefly with a shotgun, predatory mammals, fur-bearers, and most wild species considered edible had already been extirpated from most of Massachusetts before he had much chance to see or kill them.” [1]

That was 1916. How to explain “Feral Cats and Their Management,” written 94 years later—in, presumably, a very different context? The answer—part of it, anyhow—may lie with one of the paper’s co-authors, Stephen Vantassel, whose PhD dissertation was dedicated to:

“…fur trappers who, every winter, brave the harsh weather in continuance of America’s oldest industry. Regrettably, they must also endure the ravages of urban sprawl and the derision of an ungrateful and ignorant public.” [6]

I don’t mean to take anything away from Stephen Colbert and Jon Stewart, but it sometimes seems as if our politicians craft legislation with the sole intent of scoring priceless airtime on the The Colbert Report or The Daily Show. Little wonder these shows are both incredibly popular and enduring: the material just keeps coming.

And, really, you can’t make this stuff up.

Last week, Colbert took Utah Representative (and Buddhist) Curtis Oda (R) to task for his sponsorship of HB 210, which “amends provisions of the Utah Criminal Code relating to animal cruelty and animal torture,” including allowances for “the humane shooting or killing of an animal if the person doing the shooting or killing has a reasonable belief that the animal is a feral animal.”

As for what constitutes “humane” or “reasonable,” that’s anybody’s guess—plenty of grist for Colbert’s mill…

I’ll leave it to others (Stephen Colbert, are you listening?) to poke holes in the theological rationale put forth by Dr. Clayton M. White, professor emeritus at Brigham Young University, and his nameless co-author—but can’t help weighing in on their science:

“In Wisconsin alone, where data are good, about 39 million native animals are killed annually by pet and feral cats.”

That’s right: despite their combined “90 years of work in zoology and conservation,” these two are trying to sell the Wisconsin Study’s estimates as actual data (and, by association, the Wisconsin Study as an actual study).

As I pointed out in my first post on the topic, Olof Liberg did not differentiate between native and non-native prey, as Hildreth, Vantassel, and Hygnstrom suggest. In fact, his reference to “natural prey” [1] was only to distinguish between food provided by humans and any wildlife that cats might consume.

While revisiting Liberg’s paper, though, I found something far more intriguing: it appears Hildreth, Vantassel, and Hygnstrom never made it past the abstract.

In their report, the authors write: “The diets of well-fed house-based cats in Sweden consisted of 15 percent to 90 percent native prey, depending on availability.” [2] But what Liberg is describing here is merely the range of prey brought in by all of the cats in the study, 80–85 percent of which were “well-fed house-based” (the others feral).

Moving beyond the abstract, however, the story gets even better. Averaged annually, wildlife makes up just 25–30 percent of the diet of the owned cats (see Fig. 1). Rabbits, being abundant in the area, make up the bulk, with birds—which, we’re made to understand, are of greatest concern for Hildreth, Vantassel, and Hygnstrom—comprising a couple percent at most.

* * *

Considering the brevity of the report’s Issues and Impacts section (roughly the same space as was allotted to lethal control methods), the authors managed to squeeze in a surprising amount of misinformation.

In my haste to get my previous post online, I neglected to address a critical point (later brought to my attention by a particularly helpful reader). So, a brief follow-up…

In “Feral Cats and Their Management,” the authors point out—correctly, in this case—that “most feral cats (62 percent to 80 percent) tested positive for toxoplasmosis.” [1] But the rate of cats testing positive—or seroprevalence—is not a useful measure of their ability to infect other animals or people.

According to Dubey and Jones, “Most cats seroconvert after they have shed oocysts. Thus, it is a reasonable assumption that most seropositive cats have already shed oocysts.” [2]

And so, any argument for killing feral cats based on their high T. Gondii seroprevalence is deeply flawed (and, it should be obvious, on very shaky ground ethically). According to this line of reasoning, we might well consider quarantining humans testing positive for flu antibodies.

TNR: The Solution, Not the Problem
If T. gondii in feral cats is really the concern, then the focus should be on removing young cats from “high-risk” environments. Sound familiar? That’s a significant part of what TNR programs do.

As Dubey and Jones point out, T. gondii prevalence tends to be higher in feral cats than pet or owned cats. [2] So, getting kittens adopted—a key feature of TNR—reduces the likelihood of their becoming T. gondii “contributors” in the future.

One can actually make the argument that TNR—dismissed more or less out of hand by Hildreth, Vantassel, and Hygnstrom—may well be the best defense currently available against the spread of Toxoplasmosis (not only in terms of stabilizing/reducing population numbers overall, but also in that it reduces number of kittens potentially exposed to T. gondii).

Hunting for Scapegoats
Finally, one more interesting note from Dubey and Jones (whose paper is referenced in “Feral Cats and Their Management”):

“In addition to live prey, eviscerated tissues (gut piles) from hunted deer and black bears would be a source of infection for wild cats… Prevalence of T. gondii in wild game and venison in the USA is very high and hunters need to be aware of the risk of transmission of infection to humans and, more importantly, spread of infection in the environment. The viscera of hunted animals need to be buried to prevent scavenging by animals, especially cats.” [2]

But Hildreth et al. prefer to focus (or, take aim, as the case may be) solely on feral cats. Though their motives aren’t clear to me, there’s no doubt whatsoever that they have little understanding of the key issues surrounding TNR—never mind the relevant science.

That’s what somebody posted on the Vox Felina Facebook page late last night—along with a link to an MSNBC news story. The headline was an attention-getter, no doubt about it: “Report: Kill feral cats to control their colonies.”

“The report began in an undergraduate wildlife management class, with students writing reports on feral cats based on existing research. The students’ professor and other [University of Nebraska] researchers then compiled the report from the students’ work.” [1]

“Feral Cats and Their Management” claims, straightforwardly enough, to provide “research-based information on the management of feral cats.” [2] Management, in this case, meaning—as is so often the case in such contexts—killing, extermination, eradication, and so forth. Detailed advice is provided (e.g., “Body-gripping traps and snares can be used to quickly kill feral cats”).

It’s no surprise that the authors of the report offer no evidence to support such a sweeping claim. “There are few if any studies,” write Mike Fitzgerald and Dennis Turner in their contribution to The Domestic Cat: The biology of its behaviour, “apart from island ones that actually demonstrate that cats have reduced bird populations.” [3]

Biologist C.J. Mead, reviewing the deaths of “ringed” (banded) birds reported by the British public, suggests that cats may be responsible for 6.2–31.3% of bird deaths. “Overall,” writes Mead, “it is clear that cat predation is a significant cause of death for most of the species examined.” Nevertheless, Mead concludes, “there is no clear evidence of cats threatening to harm the overall population level of any particular species… Indeed, cats have been kept as pets for many years and hundreds of generations of birds breeding in suburban and rural areas have had to contend with their predatory intentions.” [4]

The German zoologist Paul Leyhausen (1916–1998), who spent the bulk of his career studying the behavior of cats, found that cats, frustrated by the difficulties of catching them, “may soon give up hunting birds.” [5]

“During years in the field,” wrote Leyhausen, “I have observed countless times how cats have caught a mouse or a rat and just as often how they have stalked a bird. But I never saw them catch a healthy songbird that was capable of flying. Certainly it does happen, but, as I have said, seldom. I should feel sorry for the average domestic cat that had to live solely on catching birds.” [5]

“Cats kill an estimated 480 million birds per year (assuming eight birds killed per feral cat per year).”

Fitzgerald and Turner (whose work is not referenced in the report) argue that “we do not have enough information yet to attempt to estimate on average how many birds a cat kills each year.” [3] Though, of course, many studies have tried to do exactly that—few, it should be said, involve feral cats.

“Estimates from Wisconsin indicate that between 500,000 and 8 million birds are killed by rural cats each year in that state…”

How anybody could misquote the numbers from the Wisconsin Study—easily the most widely circulated work on the subject—is a mystery. (On the other hand, the figures were, as Stanley Temple has said, “not actual data” [6] in the first place, so I suppose that does allow for some rather liberal interpretation.)

How important is it that the prey of feral cats is native, versus non-native? That’s a point of some debate—but not in this case. See, what Liberg actually wrote was this: “Most cats (80-85%) were house-based and obtained from 15 to 90% of their food from natural prey, depending on abundance and availability of the latter.” [7, emphasis mine] He was merely drawing the distinction between food provided by humans and any prey that cats might eat as food.

“In California, 67 percent of rodents, 95 percent of birds, and 100 percent of lizards brought home by cats were native species, and native birds were twice as likely to be seen in areas without cats.”

What looks to be truly damning evidence loses much of its impact when it’s seen in context. The reference to Crooks and Soulé’s 1999 paper, for example, omitted the sample size involved: “Identification of 68 prey items returned by cats bordering the fragments indicated that 67% of 26 rodents, 95% of 21 birds and 100% of 11 lizards were native species.” [8] It’s important to note, too, that these researchers asked residents to recall what kind of prey their cats returned—no prey items were collected—thereby raising questions about the accuracy of species attribution.

Furthermore, the cats involved with Crooks and Soulé’s study were all pet cats. How their habits compare with those of feral cats is an open question. Merritt Clifton of Animal People, an independent newspaper dedicated to animal protection issues, suggests, “feral cats appear to hunt no more, and perhaps less, than free-roaming pet cats. This is because, like other wild predators, they hunt not for sport but for food, and hunting more prey than they can eat is a pointless waste of energy.”

The second portion of the quote refers to Cole Hawkins’ PhD dissertation. Hawkins’ research methods and analysis are so problematic that the suggestion of a causal relationship between the presence of cats and the absence of birds (native or otherwise) is highly inappropriate (indeed, Hawkins scarcely investigates predation at all).

Among the key issues: Hawkins had no idea what the “cat” area of his study site was like before the cats were there; he merely assumes it was identical to the “no cat” area in terms of its fauna (though the two landscapes are actually quite different). It’s also interesting to note Hawkins’ emphasis on “the preference of ground feeding birds for the no-cat treatment” while downplaying the fact that five of the nine ground-feeding species included in the study showed no preference for either area. (For a more comprehensive analysis, please see my previous post on the subject.)

“…cats are the most important species in the life cycle of the parasite responsible for toxoplasmosis, and in 3 separate studies, most feral cats (62 percent to 80 percent) tested positive for toxoplasmosis.”

While cats are the “definitive host,” it’s important to note that “wild game can be a source of T. gondii infection in humans, cats, and other carnivores. Serologic data show that a significant number of feral pigs, bears, and cervids are exposed to T. gondii.” [9]

“Humans,” write Elmore et al., “usually become infected through ingestion of oocyst-contaminated soil and water, tissue cysts in undercooked meat, or congenitally. Because of their fastidious nature, the passing of non-infective oocysts, and the short duration of oocyst shedding, direct contact with cats is not thought to be a primary risk for human infection.” [10]

Toxoplasma gondii has been linked to the illness and death of marine life, primarily sea otters [11], prompting investigation into the possible role of free-roaming (both owned and feral) cats. [12, 13] It’s generally thought that oocysts (the mature, infective form of the parasite) are transferred from soil contaminated with infected feces to coastal waterways by way of freshwater run-off. [13]

However, a 2005 study found that 36 of 50 sea otters from coastal California were infected with the Type X strain of T. gondii [14], a type linked to wild felids (mountain lions and a bobcat, in this case), but not to domestic cats. [13] A recently published study from Germany seems to corroborate these findings. Herrmann et al. analyzed 18,259 fecal samples (all from pet cats) for T. gondii and found no Type X strain. (It’s interesting to note, too, that only 0.25% of the samples tested positive for T. gondii).[15]

[NOTE: Please see follow-up post for additional information about cats and T. gondii.]

“Predation by cats on birds has an economic impact of more than $17 billion dollars [sic] per year in the U.S. The estimated cost per bird is $30, based on literature citing that bird watchers spend $0.40 per bird observed, hunters spend $216 per bird shot, and bird rearers spend $800 per bird released.”

According to this bizarre form of accounting, hunters value an individual bird more than 500 times as much as a birdwatcher does—suggesting, it seems, that dead birds are far more valuable than live birds. This is the kind of estimate that can be developed only through university (or perhaps government) research efforts.

Public Indecency
“Stephen Vantassel, a wildlife damage project coordinator who worked on the study, said researchers were aware that some people would be ‘very offended that we offered any type of lethal control method.’ But he said the report was written for public consumption and wasn’t submitted to any science journals for publication.” [1]

For the record, Dr. Vantassel, I’m more offended by the way you’ve allowed such sloppy, grossly irresponsible work to pass for “research.” And the idea that such an undertaking is somehow acceptable because it’s meant for a mass audience is simply absurd!

Naturally, the American Bird Conservancy (ABC) embraced the report immediately, “with one official calling it ‘a must read for any community or government official thinking about what to do about feral cats.’” [1]

“‘Not surprisingly, the report validates everything American Bird Conservancy has been saying about the feral cat issue for many years—namely, TNR doesn’t work in controlling feral cat populations,’ Darin Schroeder, vice president of the Conservation Advocacy for American Bird Conservancy, said Tuesday.”

But validation requires far more than this report provides—beginning with a real interest in scientific inquiry and some basic critical thinking skills. And while we’re at it, a refresher in ethics wouldn’t hurt, either.